Experimental and numerical investigation of failure ina commercial dual phase steel and the effect ofmicrostructure on that

Dual phase (DP) steels have a microstructure consisting of a ferrite matrix, in which particles of martensite are dispersed. In this work both experimental and numerical methods were employed to investigate the mechanism of failure in DOCOL 600 DP steel. The tensile test for specimens was interrupted in different steps, to capture the mechanism of void initiation and void growth during material failure. Specimens areselected to be parallel to rolling direction and normal to rolling direction. Several kinds of voids in microscopic figures were observed. The macroscopic pattern and microscopic phase’s orientation in failure zone were analyzed. The finite element model of the real microstructure isused and analyzed in order to predict the material behavior. Numerical simulations are able to predict the void initiation in the material. The stress Distribution and plastic strain Distribution reported from the numerical simulation on real micro-structure of material. Deformation localization, which causes severely deformed regions in the material, is most probably the main source of rupture in the final stages of the failure. In the SEM micrographs of the material after failure some voids are observable which can validate the results obtained by the simulation.

کلیدواژه ها:

Dual phase steel ، failure process ، void initiation ، tensile test